Simple budget for a tight month - first time posting

My income is now a fraction of what it was as a marketing coordinator and I am trying to cover the essentials. I have been trying to stay organised about it. I am nervous about falling behind. Any apps or methods?

Sell things you do not use. I made about $650 from a weekend of listing.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.